1. Field of the Invention
The present invention relates to a support column for underground longwalls, roads, galleries or tunnels. The support column includes two telescoping hollow column components which are guided against each other. The lower of the column components can be filled with a non-hardening filler and is provided with a closable outlet opening.
2. Description of the Related Art
Support columns which can be filled with a hardening filler are known in the art. Prior to filling, these support columns are clamped or propped against the hanging wall and the foot wall or against the roof and the floor. In this connection, it is known from DE 28 47 906 to provide an auxiliary stay which remains in the column until the filler has hardened. DE 29 41 663 proposes the use of a clamping securing means in the form of a section ring with a cutting edge. In accordance with DE 39 15 837, the support column is clamped by means of a winding mechanism which is arranged in the support column. DE 41 15 209, which corresponds to U.S. patent application Ser. No. 07/934,660, now U.S. Pat. No. 5,273,378, describes a ring-shaped spring element as a clamping means.
All the above-described clamping means have in common that the support column is first clamped and the filler is filled in subsequently. After the filler has been filled into the support columns, the auxiliary means used for clamping lose their function. In addition, the above-described support columns have in common that they cannot be removed after clamping or placing. Accordingly, an economical utilization of material is possible only to a limited extent when such support columns are used.
U.S. Pat. No. 1,765,200 discloses a support column which includes two telescoping hollow column components which are guided against each other, wherein a non-hardening filler can be filled into the lower column component and the lower column component is provided with a closable outlet opening. The filler may be stone dust, sand or another suitable granulated material having a small grain size. The filler can be introduced into the column component by removing a base plate of the lower column component. The filler may also be introduced through a suitable opening in the base plate or in the wall of the lower column component. This opening is closed by a suitable closing member. Alternatively, the filler can also be introduced into the lower column component by removing the upper column component.
The bottom of the upper column component has a cutout which may have various configurations. Above the cutout, the interior space of the lower column component is in permanent connection with the interior space of the upper column component. The fact that the two interior spaces are connected results in the disadvantage that the support column cannot be clamped with a certain setting load. In addition, this support column has a resilient behavior because, when forces act in longitudinal direction of the support column, the filler can penetrate from the interior space of the lower column component through the cutout in the bottom of the upper column component into the interior space of the upper column component. Moreover, excess filler can be discharged out of the interior space of the upper column component through an opening in a cover plate of the upper column component.